This application relates to scanning-beam display systems.
In a scanning-beam display system, an optical beam can be scanned over a screen to form images on the screen. Many display systems such as laser display systems use a polygon scanner with multiple reflective facets to provide horizontal scanning and a vertical scanning mirror such as a galvo-driven mirror to provide vertical scanning. In operation, one facet of the polygon scanner scans one horizontal line as the polygon scanner spins to change the orientation and position of the facet and the next facet scans the next horizontal line. The horizontal scanning and the vertical scanning are synchronized to each other to project images on the screen.
Such scanning-beam display systems can be in various configurations. For example, scanning-beam display systems may use passive screens that do not emit light but make light of the scanning beam visible to a viewer by one or a combination of mechanisms, such as optical reflection, optical diffusion, optical scattering and optical diffraction. Examples of such displays include digital light processing (DLP) displays, liquid crystal on silicon (LCOS) displays, and grating light valve (GLV) displays. Various front and rear projection displays use passive screens. Scanning-beam display systems can also use active screens such as fluorescent screens that include fluorescent materials to emit colored light under optical excitation where the emitted light forms the images visible to viewers. Examples of such display systems include cathode-ray tube (CRT) displays, plasma displays, liquid crystal displays (LCDs), light-emitting-diode (LED) displays (e.g., organic LED displays), and field-emission displays (FEDs).